This work belongs to the development of mechanical force-responsive drug delivery systems based on remote stimulation by an external magnetic field at the first stage, assisting the positioning of a ferrogel-based targeted delivery platform in a fluid flow. Magnetically active biopolymer beads were considered a prototype implant for the needs of replacement therapy and regenerative medicine. Spherical calcium alginate ferrogels (FGs)~2.4 mm in diameter, filled with a 12.6% weight fraction of magnetite particles of 200-300 nm in diameter, were synthesized. A detailed characterization of the physicochemical and magnetic properties of FGs was carried out, as were direct measurements of the field dependence of the attractive force for FG-beads. The hydrodynamic effects of the positioning of FG-beads in a fluid flow by a magnetic field were studied experimentally in a model vessel with a fluid stream. Experimental results were compared with the results of mathematical and computer modeling, showing reasonable agreement. The contributions of the hydrodynamic and magnetic forces acting on the FG-bead in a fluid flow were discussed. Obtained forces for a single ferrogel implant were as high as 0 to 10 N for the external field range of 0 to 35 kA/m, perfectly in the range of mechanical force stimuli in biological systems.
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http://dx.doi.org/10.3390/gels9090711 | DOI Listing |
Fluids Barriers CNS
January 2025
Medical Image Processing Department, CHU Amiens-Picardie University Hospital, Amiens, France.
Background: The pressure gradient between the ventricles and the subarachnoid space (transmantle pressure) is crucial for understanding CSF circulation and the pathogenesis of certain neurodegenerative diseases. This pressure can be approximated by the pressure difference across the aqueduct (ΔP). Currently, no dedicated platform exists for quantifying ΔP, and no research has been conducted on the impact of breathing on ΔP.
View Article and Find Full Text PDFCardiovasc Eng Technol
January 2025
Transonic Systems Inc., 34 Dutch Mill Road, Ithaca, New York, 14850, USA.
Purpose: Over time, transit time flow measurement (TTFM) has proven itself as a simple and effective tool for intra-operative evaluation of coronary artery bypass grafts (CABGs). However, metrics used to screen for possible technical error show considerable spread, preventing the definition of sharp cut-off values to distinguish between patent, questionable, and failed grafts. The simulation study presented in this paper aims to quantify this uncertainty for commonly used patency metrics, and to identify the most important physiological parameters influencing it.
View Article and Find Full Text PDFSci Rep
January 2025
Key Laboratory of Gas and Fire Control for Mines, Ministry of Education, Xuzhou, 221116, China.
Confined space fires could easily cause serious casualties and property damage, and foam is an effective means of preventing confined space fires. The existing foam generator does not have both momentum and foam expansion rate (FER) and is poorly suited to confined spaces. In order to develop a foam generator suitable for confined space fire protection, an in-depth analysis of the physical foaming characteristics of self-suction foam is required, and the structure of the foam generator is optimized accordingly.
View Article and Find Full Text PDFSci Rep
January 2025
School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 102488, China.
The main advantages of microneedles are precise drug delivery through human skin, minimal tissue damage and painlessness. We conducted structural analysis and skin puncture studies of hollow microneedles using ANSYS for three materials: Hafnium Dioxide (HfO), Polyglycolic acid (PGA) and Polylactic acid (PLA). Firstly, we selected three lengths, three tip diameters and three base diameters to conduct a L(3) orthogonal experiment.
View Article and Find Full Text PDFNeuroimage
January 2025
Department of Radiology, Mayo Clinic, Rochester, MN, USA. Electronic address:
Cardiorespiratory signals have long been treated as "noise" in functional magnetic resonance imaging (fMRI) research, with the goal of minimizing their impact to isolate neural activity. However, there is a growing recognition that these signals, once seen as confounding variables, provide valuable insights into brain function and overall health. This shift reflects the dynamic interaction between the cardiovascular, respiratory, and neural systems, which together support brain activity.
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